A technique for manufacturing a microcrystalline semiconductor layer with high mass productivity is provided. In a reaction chamber of a plasma CVD apparatus, an upper electrode and a lower electrode are provided in almost parallel to each other. A hollow portion is formed in the upper electrode, and the upper electrode includes a shower plate having a plurality of holes formed on a surface of the upper electrode which faces the lower electrode. A substrate is provided over the lower electrode. A gas containing a deposition gas and hydrogen is supplied to the reaction chamber from the shower plate through the hollow portion of the upper electrode, and a rare gas is supplied to the reaction chamber from a portion different from the upper electrode. Accordingly, high-frequency power is supplied to the upper electrode to generate plasma, so that a microcrystalline semiconductor layer is formed over the substrate.